Online effective backscattering estimation for ring laser gyro

Lock-in phenomenon in ring laser gyroscopes is directly related to effective backscattering, which includes both backscattering and nonuniform loss. Effective backscattering often differs in different states and can only be reflected in a working state via online estimation in the working state. Moreover, effective backscattering can result in the intensity modulation of beams in the opposite directions. The effective backscattering parameters can be obtained by measuring the weak modulations in the intensity signals under different rotation rates and by using the curve-fitting method. This letter demonstrates the online estimation of backscattering.